This tag has a diameter of 13mm and an overall thickness of about 2mm. They are also waterproof for use in laundry. It works with MIFARE 13.56 MHz compatible readers.
The MIFARE Classic card is fundamentally just a memory storage device, where the memory is divided into segments and blocks with simple security mechanisms for access control. They are ASIC based and have limited computational power. Thanks to their reliability and low cost, these tags are widely used for electronic wallet, access control, corporate ID cards, transportation or stadium ticketing.